public class MySingleList implements IList{
    //节点的内部类
    static class ListNode {
        public int val;
        public ListNode next;
        public ListNode(int val){
            this.val = val;
        }
    }
    public ListNode head;//链表的成员不是节点的成员
    public void createList(){
        ListNode node1 = new ListNode(12);
        ListNode node2 = new ListNode(23);
        ListNode node3 = new ListNode(34);
        ListNode node4 = new ListNode(45);
        ListNode node5 = new ListNode(56);

        node1.next = node2;
        node2.next = node3;
        node3.next = node4;
        node4.next = node5;
        
        this.head=node1;

    }

    @Override
    public void addFirst(int data) {
        ListNode node = new ListNode(data);
        if(this.head==null){
            this.head= node;
        }else{
            node.next = this.head;
            this.head=node;
        }
    }

    @Override
    public void addLast(int data) {
        ListNode cur = this.head;
        ListNode node  = new ListNode(data);
        if(this.head==null){
            this.head = node;
        }else{
            while(cur.next!=null){
                cur = cur.next;
            }
            cur.next = node;
        }
    }

    @Override
    public void addIndex(int index, int data) throws ArithmeticException{
        //自定义异常
        if(index<0||index>size()){
             throw new ArithmeticException("抛出下标"+index+"异常");

        }

        if (index == 0) {
            addFirst(data);
            return;
        }
        if (index == size()) {
            addLast(data);
            return;
        }
        ListNode cur = searchPrev(index);
        ListNode node = new ListNode(data);
        node.next = cur.next;
        cur.next = node;

    }
       private ListNode searchPrev(int index){
           ListNode cur = this.head;
           int count = 0;
           while(index-1!=count){
               cur= cur.next;
               index--;
           }
           return cur;
    }



    @Override
    public boolean contains(int key) {
        ListNode cur = this.head;
        while(cur!=null){
            if(cur.val==key){
                return true;
            }
            cur = cur.next;
        }
        return false;
    }

    @Override
    public void remove(int key) {
        if(this.head==null){
            //一个节点都没有
            return;
        }
        if(this.head.val==key){
            this.head = this.head.next;
            return;
        }
        //1.找到前驱

        ListNode cur = findPrev(key);
        //2.判断返回值是否为空
        if(cur==null){
            System.out.println("没有你要删除的元素");
            return;
        }
        //3.删除操作
        ListNode del = cur.next;
        cur.next = del.next;

    }
    //找到关键字key前一个地址
    private ListNode findPrev(int key){
        ListNode cur = this.head;
        while(cur.next!=null){
            if(cur.next.val==key){
                return cur;
            }
            cur = cur.next;
        }
        return null;
    }

    @Override
    public void removeAllKey(int Key) {
        if (this.head == null) {
            return;
        }
            ListNode prev = head;
            ListNode cur = head.next;
            while (cur != null) {
                if (cur.val == Key) {
                    prev.next = cur.next;
                    cur = cur.next;
                }else {
                    prev = cur;
                    cur = cur.next;
                }
            }
            if(head.val ==Key){
                head = head.next;
            }
        }


    @Override
    public int size() {
        int count = 0;
        ListNode cur = this.head;
        while(cur!=null){
            count++;
            cur = cur.next;
        }

        return count;
    }

    @Override
    public void clear() {

    }

    @Override
    public void display() {
        ListNode cur = this.head;
        while(cur!=null){
            System.out.println(cur.val +" ");
            cur = cur.next;
        }

    }

}
